Call box



E. A. DEMONET CALL BOX Filed Sept. 1; 1933 FIG 2 f lllllll lllifilllllllllifi? INVENTQR E. A. DEMONET @wsw JLQATTADRNEY I Patented Apr.27, 1937 Y UNlTED s'rArss rarest OFFICE CALL BOX Eugene A. Demonet,Brooklyn, N. 55., assignor to The Western Union Telegraph Company, NewYork, N. Y., a corporation of New York Application September 1, 1933,Serial No. 687,891

6 Claims. (01. 1s5 37) This invention relates to apparatus, such as workmechanism, having an escapement for govmessenger call boxes, for sendingfrom an outerning the speed of operation. Control means post station toa central station a predetermined is provided for starting the operationof the code signal which will indicate from which outclockwork mechanismand permitting it to conpost station the call is coming. tinue until thecode wheel has made a complete 5 The apparatus to which this inventionrelates revolution. This is usually provided by stop is known in the artas call boxes and the primechanism on the main drive shaft which isconmary object of this invention is to construct nected to a windinghandle at the front or top v a call box mechanism for sendingsig-nals'from of the box and which permitsthe clock mechalO the callingstation which may be inexpensive to nism to be wound only a sufi'icientamount to manufacture, yet employing component parts of drive themechanism through a complete revolusimple and rigid construction. tionof the code wheel. 7

Another object of this invention is to con- Due to the fact that callboxes are installed in struct a call box employing a minimum numberlocations of such widely varying conditions and it of component partswhich maybe easily and are operated y infrequently, it s necessaryreadily assembled into a complete mechanism. that the spring motor fordriving the mecha- A further object of this invention is to pronismshall be strong enough to insure the operavide a spring motor escapementmechanism tion of the call box at all times. Therefore, the which willoperate with the minimum Wear and escapement mechanism is called upon toescape g0 noise. 7 a relatively large amount of motive forces. Here- Astill further object of this invention is to tofore, the escapementprovided for call boxes, .provide'aworm and Worm wheelescapement drivein substantially all cases, comprised vibrating which embodies anon-reversing arrangement. or oscillatory escape pallets operating uponthe These and other objects will be apparent from teeth of an esoapementwheel. In order for such the following description and claims taken intype of escapement to be compact and capable 25 connection with theaccompanying drawing, in of dissipating a large amount of motive forceit which: has been necessary to devise the mechanism of Fig. 1 is a sideelevation of the call box mechheavy parts accurately made. Also towithstand anism with the Cover, sectioned t0 D S the the vibration setup by a vibratory or oscillatory mechamsm; escape, it has also beennecessary to manufac- 30 2 is a p View p y Section taken ture otherparts of the call box mechanism along along the line 22 of Fig. 1 withthe cover rea correspgnding 5331a moved; However, according to thisinvention a type of l IS a detall 0f the W and Worm Wheel escapement isemployed which substantially elimlllustratlngthe no-ll-reverslngfeature, and inates vibration and which materially reduces 35 Fi 4 s aSection P View Of the main Spring the noise and which may be easily andcheaply mechanism taken along the line of made from small andinexpensive parts. With Heretofore call box mechanisms have been contheuse of this type of escapement the expenstructed in such a manner thatthe various comsive design of the other parts of the mechanism 40 pcnentparts of the mechanism had to be manare correspondingly cut down. 40ufactured with a high degree of accuracy in order For a more completedescription, reference will for the mechanism to function properly andhave now be had to the drawing, which shows a base long life. Therefore,call boxes have been an item it upon which the mechanism is mounted, andof relatively high cost considering the simplicity a cover I I arrangedto fit upon the base and cover 4.5 of the operations which they arecalled upon to the mechanism, and a handle l2 which is roperform. tatedfrom one of its stop limits to the other Basically a call boxincorporates a code wheel for sending out the call. which is usually inthe nature of a disk hav- The call box mechanism itself comprises uppering a predetermined number of notches cut in and lower frame plates [3and 14 between which its periphery and spaced from each other in'a thespring motor and clockwork mechanism is 50 predetermined order so thatas it rotates under assembled. The plates are held apart by spacing astationary brush a circuit is opened and'closed posts l5 of which thereare three. The plates 13 in such a manner as to send out a code signal.and M are pierced for admitting the various This code wheel is rotatedat a substantially'unishafts and screws of the mechanism. The motor '55form speed by means of a spring motor and clockmechanism embodies a maindrive shaft I6 which carries a main drive gear I! loosely mountedthereon, a click pawl I9, a stop arm 2! and the handle I2. A driveSpring 22 has its outer end looped about one of the spacer posts I5 andits winding end secured to the drive shaft by means of the usual pinprotruding therefrom and engaging in a slot at the inner portion of thespring in a well known manner. The drive shaft extends from below thebottom plate I l up through the top plate I3 and through an opening inthe cover II to engage the operating handle I2.

It will be observed that the main drive shaft I6 is a square bar havingthe same cross section from end to end. This type of drive shaft hasmany advantages over the ordinary round shaft in that it embodies keyingsurfaces throughout its length making it unnecessary to prepare specialsurf-aces for mounting the various elements. The outer end of the driveshaft extends into a square hole in the handle which is held to theshaft by any suitable locking means as by a screw 9. The stop arm 2I isprovided with a square hole to permit it to slide into place over thedrive shaft and is held by set screw 23 just above plate I3. Next belowplate I3 is a thrust washer 24 which provides a seat for compressionspring 25 surrounding the drive shaft. The lower end of the compressionspring is seated against a spider member I9 which acts as the drivingratchet pawl. The pawl I9 is provided with a square hole at the centerby means of which it is keyed to the drive shaft and is free to movelongitudinally along the shaft against the action of the compressionspring 25. Below the pawl is a ratchet plate member 26 which is madefast to the main drive gear I! by means of rivets 21. The teeth of theratchet are struck up from the plate.

When these elements are assembled on the drive shaft the elements inorder are: the main spring 22, the drive gear I! resting together withits associated ratchet 26 on the upper side of the drive spring 22, thepawl I9, the spring 25 and the thrust washer 24. The compression spring25 interposed between the floating pawl and the upper plate performs twofunctions, the function of holding the pawl member I9 in yieldingengagement against the ratchet plate member 26 so that the click actionmay take place and also the function of holding the main drive gear I!in proper position.

Referring particularly to Figure 2, it will be seen that the pawl memberI9 embodies three radially extending arms having their forward edgesstraight and their rearward edges bent slightly upward. The ratchetmember on the other hand embodies six teeth 20 which are formed bystriking up arcuate Segments from the plate 26. The edges of the struckup portions are arranged to be engaged by the forward edges of the pawlarms when the spring 22 is exerting a drive action on the gear. Forwinding the drive spring the main drive shaft is turned by gripping thehandle I2 as shown in Fig. 1 and rotating it clockwise. As the pawlmember moves over the ratchet disk the bent up portion of the back ofthe pawl arms rides on the upstanding ratchet teeth so as to elevate thepawl plate until the arms click over the ratchet teeth. Upon releasingthe handle I2, it will be seen that the loosely mounted gear I1 iscaused to rotate in a counterclockwise direction through the action ofthe spiral spring 22 through the intermediary of the pawl I9 and theteeth of the ratchet plate 26. In an alternative arrangement the ratchetteeth, instead of being formed from a plate or disk, may be struck upfrom the body of the main gear. In either case the operation of theratchet pawl is substantially the same.

With this arrangement the main gear I! engages the pinion 28 of theshaft 28 which carries the code disks 29 and 30. Arms 3| engage theteeth of the disks as they rotate to produce signals in a well knownmanner.

It will be observed that the ratchet plate employs six teeth andprovides six positions in which the pawl may engage the ratchet. Theratio of the number of teeth in the pinion 28 to the main gear is suchthat the shaft 28 makes a complete revolution for one sixth of arevolution of the main gear. In order to limit the operation of the codedisks to the sending of one code series of signals for each windingoperation of the handle, the movement of the drive shaft I6 is limitedby means of suitable stop pins 32 spaced in such angular relation as topermit the arm 2I to turn a little more than one sixth of a revolutiontherebetween. The pin upon which the arm normally rests arrests theaction of the main spring upon the drive gear by stopping the motion ofthe main shaft. The other pin arrests the winding motion of the mainshaft when the handle is turned the distance of one sixth of arevolution plus the distance allowed for insuring the click arms of thepawl dropping in place.

A second gear wheel 33 made fast to the shaft 28 engages the pinion 34'on the shaft 35 of the escape worm wheel 35. The escape worm wheelengages the worm 31 on a shaft 38 which is mounted between screws 39 andII set in members struck up from the bottom plate I4.

In manufacture the shaft 28' and 35 are made from stock bars known aspinion rod which may be obtained very cheaply in any quantity fromregular commercial stock. The shaft 28 is formed by turning down theupper portion or the section of rod to the proper size to form a journaland to receive the code disks 29 and 30. The lower journal of the shaftis likewise formed by turning down the other end of the pinion rod. Thegear wheel 33 is mounted upon a section of the shaft which is turneddown just a sufiicient amount to form shoulders on the pinion teethagainst which the gear may rest. The gear is stamped out with a centralhole of star-shape of a suitable size to fit over the stub teeth belowthe shoulders. The shaft and gear is assembled by pressing the gear onthe stub teeth and held in place by upsetting the portion of the teethextending beyond the gear or by soldering the gear in place or othersuitable means. The worm gear shaft 35 is formed in substantially thesame manner by turning down one end of the pinion rod from which theshaft is formed to admit the worm gear substantially in the same manneras just described for the foregoing shaft. Journals are formed on theopposite ends of the shaft 35 by turning the pinion rod down to suitablesize. From this it will be observed that these two shafts may be madevery cheaply with a minimum number of operations and without supplyingany additional elements or parts to complete the shaft or gear unit.

The escapement shaft 38 escapes the driving force of the main spring bythe use of well known restrained fly-ball type of governor. Thiscomprises a pair of weights 42 carried by spring arms 43 extendinglongitudinally of the shaft and secured to collar 44 which is rigid with:the shaft. The weights are arranged to rotate internally of a drum orcollar member 45. As the rotating weights gain speed they. move outagainst the spring action of the arms 43 until they engage the innersurface of the drum. This engagement tends to slowdown the speed ofrotation of the governor shaft, decreasing the force with which theweights engage the drum. As is well understood, a definite orpredetermined speed is 'quite well maintained by the equalizationbetween the tendency of the rubbingaction on the drum to. increase asthe speed increases and the tendency for it to decrease as the speeddrops against the friction produced by the weights as they engaged thedrum.

Carrying out the idea of inexpensive companion parts, the worm 3'! ofthe governor or worm shaft 38 is formed by winding a wire spirally about.the shaft and soldering or welding the same thereto. This forms acombined worm and worm gear which under test has operated to theequivalent of 20 years average life service of a call box mechanismwithout appreciable wear.

One of the conditions encountered in employing a worm and worm wheelescapement .in a clock work mechanism which is wound by rotating themain drive shaft in the reverse direction,

particularly in mechanisms of the type herein provided in which aconsiderable amount of friction is present, is the likelihood of thisfriction being sufficient tocause the gear train to rotate in a reversedirection. This is particularly objectionable for call box mechanismsemploying a code disk making contact With fingers or the like forsending out a code signaL- Besides causing the disk tosend out a falsesignal, if it should rotate while the finger is in a reverse directionit might also become jammed against the finger contacts.

It is therefore desirable to provide means to prevent the worm shaftfrom rotating in a reverse direction with the type of escapementemployed in this mechanism. This is accomplished in a very simple mannerwithout employing any over running clutch or ratchet feature such asusually required. The non-reversing means is provided 'by sloping orcutting back the points of the teeth of the worm wheel 36 so that whenthe samev is urged in a reverse direction as indicated by the dottedline arrow in Fig. 3, the end of the teeth instead of the back facethereof engages the worm 31 along its sloped surface and exerts a thrustupon the worm shaft 38 largely in a transverse direction instead oflongitudinally as in the case of the ordinary driving engagement withthe forward face of the tooth. This transverse thrust against shaft 38instead of tending to rotate the same, causes it to bind between the endof. the tooth and its hearings in the screws 39 and 4!. Therefore theworm wheel 36, as soon as it engages the worm 31 in a reverse direction,will produce the aforesaid binding action as long as the force in thedirection of the dotted arrow remains. This will be during the period inwhich the operating handle 12 is rotated in the clockwise or main springwinding direction. As soon as the spring is wound and the handlereleased, force is applied to rotate the worm wheel 36 in the directionof the solid arrow and the face of the teeth moved around into drivingengagement with the worm, permitting the mechanism to operate until themain drive shaft is rotated through its limited movement in the mannerheretofore described.

, produce substantially the same jamming action as just described,thereby applying resistance to rotation which stops the worm shaftalmost'instantly. As a result the mechanism does not continue to rotatebeyond the point set by the limit stop of the main drive shaft assuringthat the code disk is stopped substantially in the same position at theend of each period of rotation.

Referring briefly now to Fig. 4, I have shown a plan view of the mainspring 22. The inner end of the spring is secured to the shaft I6 byapin 22, and its outer end is fastened to the spacing post l5. It willbe observed that the convolutions of the spring are in closerelationship and the rivet heads 21 are sufiiciently broad and flat sothat the latter may ride on the upper edge of the spring withoutslipping down between the convolutions and causing the gear H to be heldagainst rotation. Since turning the winding handle, in order to operatethe call-box, only tightens the spring 22, the convolutions of thelatter will never separate sufliciently to allow the gear I! to slipdown.

From the foregoing description it will be observed that a call boxoperating mechanism has been devised which may be made up of ruggedinexpensive parts which can be produced by simple machine operations.Most of the parts can be produced by simple stamping and millingoperations. Although the various parts-are easily produced, each one issubstantial and rugged and'will be able to perform its function underthe circumstances of hard usage to which it may be subjected.

It will further be apparent that the number of parts entering into themechanism have been cut down to a minimum. The intermediate gear andpinion shafts being formed as a single unit with the complete shaft andgear comprising only two units is a considerable reduction in the numberof parts ordinarily employed.

Furthermore, it will be apparent that according to this invention a callbox mechanism has been provided by means of the foregoing novelconstruction which is extremely rugged in construction and accurate inoperation and which Although the principles of this invention have 1. Ina call box, a drive mechanism compris ing a main spring and a windinghandle connected together by a single drive shaft, a stop arm securedrigidly to said shaft, cooperating stops engageable by said arm to limitthe movement of said shaft, a drive gear mounted loosely upon said shaftand disposed with one face substantially in abutting relation to saidmain spring,

said drive gear carrying a plurality of ratchet teeth upon its upperface, a pawl element keyed to the shaft but movable longitudinallythereof whereby it may be cammed past said teeth in a reverse directionand a spring for holding the pawl into engagement with the ratchetteeth.

2. A call box embodying upper and-lower frame plates, a motive mechanismcomprising a main spring disposed adjacent to the lower plate, a windinghandle connected to the main spring by a single drive shaft, a stop armdisposed adjacent the upper plate and secured rigidly to said shaft,cooperating stops engageable by said arm to limit the movement of saidshaft, a drive gear mounted loosely upon said shaft and disposed withone face in abutting relation to said spring, said drive gear having aplurality of ratchet teeth struck up from its upper face, a pawl keyedto the drive shaft but movable longitudinally thereof, whereby it may becammed past said teeth in a reverse direction, said pawl embodying aplurality of arms arranged to engage simultaneously a correspondingnumber of said ratchet teeth, and a compression spring disposed betweenthe upper plate and said pawl for holding the same into engagement withthe ratchet teeth.

3. A call box embodying upper and lower frame plates, a motive mechanismcomprising a drive shaft, a main spiral spring surrounding said shaftand having its inner end secured thereto. said spring being disposedadjacent said lower frame plate, a winding handle connected to saiddrive shaft, a stop-arm disposed above and adjacent said upper frameplate and secured rigidly to said shaft, a pair of cooperating stopsengageable by said arm to limit the rotational movement of said shaft, adrive gear mounted loosely on said shaft between the upper frame plateand the main spring and adjacent the latter, said drive gear having aplurality of ratchet teeth struck up from its upper face, a pawl on saidshaft rotatable therewith and movable longitudinally therealong, and acompression spring surrounding said shaft between the upper frame plateand said pawl for urging the latter into contact with said drive gear tomaintain the pawl in a position to engage the ratchet teeth thereon,whereby the downward force of said compression spring, acting throughthe pawl and drive gear against the main spring secured to said shaft,maintains the lower end of said shaft in the bearing.

4. In a call box mechanism the combination of a spring motor assemblyincluding a drive shaft, a code wheel, a gear train connecting said codewheel with said drive shaft, a winding handle for rotating said driveshaft in a reverse direction to wind said motor, a governor comprising aworm shaft carrying fly-ball weights disposed to rotatewithin arestraining cup, a wire formed as a spiral and secured about said shaftfor forming the worm, a worm wheel disposed in driving engagement withsaid worm, the teeth of said worm wheel having a forward engaging faceformed at a slight angle from a radial line and a reverse engaging faceformed at a slight angle from a tangential line, whereby normal drivingaction occurs between the wheel and worm when the wheel tends to rotatein a forward direction, and whereby when the worm wheel tends to rotatein a reverse direction it becomes locked against the worm due to thefact that the major component of the thrust exerted against the worm bythe wheel is in a direction transversely of the worm shaft.

5. In a call box mechanism the combination of a spring motor assemblyincluding a drive shaft, a code wheel, a gear train connecting said codewheel with said drive shaft, a winding handle for rotating said driveshaft in a reverse direction to wind said motor, a governor shaftcarrying a worm, a worm wheel for driving said shaft, the teeth of saidWorm wheel having a forward engaging face formed along a substantiallyradial line and a reverse engaging face formed along a chord at a slightangle from a tangential line, whereby normal driving action between thewheel and worm when the wheel tends to rotate in a forward directionexerts a force against the worm, the major component of which isparallel to the axis of the worm shaft and whereby when the wheel tendsto rotate in a reverse direction the action of the reverse engaging faceof the teeth upon the worm produces a force, the major component ofwhich is in a direction transversely of the worm shaft causing the wheelto become locked against the worm, preventing the reverse rotation ofthe worm wheel.

6. In a call box drive mechanism, a motor assembly comprising upper andlower frame plates, a main shaft extending through said plates andbeyond the upper plate, a winding handle carried on the upper end of theshaft, a member disposed against the upper face of the upper plate andsecured to the shaft to provide means for restraining the shaft againstdownward longitudinal movement, a motor spring disposed to surround theshaft between the plates adjacent to the lower plate and having itsinner end secured to the shaft at a point spaced sufficiently from saidlower plate to provide for free movement of the spring over the lowerplate, a drive gear mounted to rotate freely upon the shaft and disposedwith its lower face in abutting relation to said spring, said drive gearhaving a plurality of ratchet teeth struck up from its upper face, aspider-plate pawl surrounding the shaft and embodying a plurality ofarms arranged to engage simultaneously a corresponding number of saidratchet teeth, said pawl being keyed to the drive shaft for transmittingthe driving force of the spring to the gear wheel, but movablelongitudinally thereof whereby it may be cammed past said teeth when theshaft is rotated in a reverse direction for winding the spring, and acompression spring disposed between the upper plate and said pawl, saidspring acting to hold the pawl plate in position against the gear andthe gear against the main spring and through said parts acting to exerta force downwardly upon the shaft at the point where the main spring issecured to the shaft and in this manner holding said parts in assembledposition and providing means for restraining the shaft against upwardmovement.

EUGENE A. DEMONET.

